Technology Memes

No microwave is a perfect Faraday cage. They also generate microwaves at five orders of magnitude or so greater than the strength of a Wi-Fi router, around 1000 watts for most models as opposed to 10-25 milliwatts for a typical Wi-Fi router. And remember that this is at the source on your router; by the time a Wi-Fi signal reaches your phone its energy is a tiny fraction of that thanks to the good old inverse cube law, probably down in the microwatt range. Microwaves are allowed to leak up to 5 milliwatts/cm up to 2" from the surface of the cavity, which by the time you divide it down with distance is still enough to mess with wireless connections in a similar frequency range out to short but noticeable real world distances.

My microwave will make my Bluetooth earbuds go haywire within a distance of about five feet, for instance, albeit tailing off sharply outside of that range. It's a similar deal with Wi-Fi inside that range. I've never owned a microwave in my life that didn't cause this type of interference.

In a "smart" microwave its antenna has to be inside its own casing somewhere, most likely only within a couple of inches of the outside of the microwave cavity. I'll bet you it doesn't work worth a damn while it's cooking.